Explain the idea known as "nationalism" and how it played a role in the weakining of the austrian and russian empires

The Austrian and Russian empire were both suffering from the different nations within their empires. Because they both had smaller nations which were very proud and wanted to gain independence, this eventutally lead to a decline of both empires. 

It should be at the center of any map going vertically: the prime meridian, as it passes through greenwich,  england, is considered 0 degrees longitude